1. Field
The present devices relate generally to pumps, fluid transfer devices, and apparatus including the same.
2. Description of the Related Art
A wide variety of fluid transfer devices, which commonly include a pump and one or more valves, are configured to transfer relatively small volumes of fluid per actuation of the pump. Implantable (or otherwise ambulatory) infusion devices, for example, frequently include a fluid transfer device that has an electromagnet pump and one or more valves. Examples of conventional electromagnet pumps for ambulatory infusion devices are disclosed in U.S. Pat. No. 6,796,777 to Falk et al. and U.S. Pat. No. 6,932,584 to Gray. Pipettors are another exemplary area where pumps and fluid transfer devices that transfer relatively small volumes of fluid per pump actuation are employed.
The present inventor has determined that conventional fluid transfer devices and pumps for small volume applications are susceptible to improvement. For example, the present inventor has determined that conventional electromagnet pumps and fluid transfer devices are relatively complex in that they include a plethora of very small components, many of which are difficult to produce and assemble, and that the complexity may reduce reliability. The present inventor has also determined that the amount of power consumed by conventional electromagnet pumps could be reduced. The present inventor has also determined that the amount of ullage in conventional pumps, which makes it difficult to pump gas bubbles, can be reduced.
Fluid transfer devices in accordance with at least some of the present inventions include a pump and a valve. The valve, which may be an inlet valve or a one-way outlet valve, includes a valve base, with a seal surface, and a resilient structure mounted in tension on the valve base. The resilient structure has a valve member movable between a closed state where the valve member engages the seal surface and an open state where at least a portion of the valve member is spaced apart from the seal surface.
Fluid transfer devices in accordance with at least some of the present inventions include a valve and a pump. The valve, which may be an inlet valve or a one-way outlet valve, includes a seal surface and a resilient membrane with a least one narrow opening and a valve member associated with the narrow opening. The resilient membrane is movable between a closed state where the valve member engages the seal surface and an open state where at least a portion of the valve member is spaced apart from the seal surface. The pump includes a piston that is biased to a rest position and is movable to a pull-back position. In those instances where the valve is an inlet valve, the piston holds the valve member against the seal surface when in the rest position.
Fluid transfer devices in accordance with at least some of the present inventions include an external housing member, an internal housing member defining a piston lumen, an outer surface having a perimeter, and a bypass aperture, a bypass channel in fluid communication with the bypass aperture, a resilient valve member that extends around the internal housing member and over the bypass aperture outlet, and a piston carried within the piston lumen.
Fluid transfer devices in accordance with at least some of the present inventions include an external housing tube, an internal housing tube defining a piston lumen and a bypass aperture, a bypass channel defined by the external housing tube and the internal housing tube in fluid communication with the bypass aperture, a valve member associated with the bypass aperture, and a piston carried within the piston lumen.
Fluid transfer devices in accordance with at least some of the present inventions include an electromagnet and a piston. The electromagnet has a coil, a case, and a core having a fluid lumen, and at least a portion of the core is located within the internal volume defined by the case. The piston, which has at least a portion that is magnetic and is located within the internal volume defined by the case, is movable relative to the core between a rest position and a pull-back position adjacent to the core, and is biased to the rest position.
Fluid transfer devices in accordance with at least some of the present inventions include an inner pump tube defining a piston lumen, an outer pump tube, a piston that does not include a fluid lumen and has at least a portion thereof mounted within the piston lumen such that a capillary seal is formed between the piston and the inner pump tube, an electromagnet including a coil carried outside the outer pump tube and a core having a fluid lumen carried inside the outer pump tube, a bypass channel defined at least in part by in the inner and outer pump tubes, and a bypass valve.
Fluid transfer devices in accordance with at least some of the present inventions include a housing defining a piston lumen, a piston stop including a fluid lumen, a piston which does not include a fluid lumen. The first end of the piston and the piston lumen together define an inlet chamber, and the second end of the piston and the piston stop together define an outlet chamber. The piston is movable between a first position where the volume of the inlet chamber is minimized and a second position where the piston abuts the piston stop and the prevents flow into the inlet of the piston stop lumen.
Infusion devices in accordance with at least some of the present inventions include a reservoir, an infusion device outlet, and a fluid transfer device as described in the preceding paragraphs of this Summary operably connected to the reservoir and the infusion device outlet.